Field of the Invention
The present invention relates to a process for preparing an alkyl-substituted aromatic hydrocarbon. More particularly, the present invention relates to a process for preparing an alkyl-substituted aromatic hydrocarbon by reacting an alkyl-substituted aromatic hydrocarbon having at least one hydrogen atom at an alpha-position in said alkyl side chain with an olefin in the presence of a solid base which is prepared from an alumina, an alkali metal hydroxide and an alkali metal or from water-containing alumina and an alkali metal at a temperature in a specific range, whereby the alpha position is alkylated.
The alkyl-substituted aromatic hydrocarbons are useful as intermediates in the production of fine chemicals such as agricultural chemicals, medicines and other chemicals and prepared by reacting the aromatic hydrocarbon having the hydrogen atom at the alpha-position in the side chain with the olefin in the presence of a base catalyst.
As the preparation process of the alkyl-substituted aromatic hydrocarbon, there is known a process which utilizes a catalyst comprising metal sodium and chlorotoluene and a process which utilizes a catalyst comprising metal sodium supported on potassium carbonate (cf. J. Am. Chem. Soc., 78, 4316 (1956), GB Patent No. 1269280 and Japanese Patent Kokai Publication No. 53229/1986).
However, the conventionally used catalysts have various drawbacks such as insufficient catalytic activities, a low yield of the alkyl-substituted hydrocarbon per a unit amount of the catalyst and troublesome separation of the catalysts from the product. Further, the conventional catalysts suffer from such problem that when they contact the oxygen and/or moisture in the air, they tend to lose their activities or they are ignited.